About DNA

Updated February 8, 2018

Contact webmaster: Rosemary at mcnerneywinkler dot com

What’s up with DNA? It’s making the news everywhere. There are blogs about DNA, webinars, Wikis, and videos. This is an overview of the three most common kinds of tests and what may be accomplished for genealogical purposes with each type. This is to simplify and make all this understandable.

-DNA testing for genealogy has been around the longest. Only males carry a Y chromosome. This DNA follows the male line, passing down in every generation from father to son. If you are a female and want to research your maiden-name line, you must get a male in your line who has that surname to test for you. This test will help you find and/or confirm the surname of a male. Beware! Non-paternal events have occurred throughout history. Some folks learn that they are not genetically the name they always believed they were. The caution here is--be prepared for the un-expected. It happens in the best of families. Your papa might not be your papa somewhere along the line. If you don’t think you can accept news like this, do not take the test. If you choose Y-DNA testing, do no less than 37 markers.

itochondrial DNA, mtDNA, is for tracing the female line—both males and females have it but only females pass it on. This is the other side of your tree, the more difficult one to follow because of all the surname changes women make on the way. It is strictly the maternal line and it goes way back. This DNA is actually more abundant and lasts longer, thus it is being used in the forensic work of identifying remains. It was used to identify the family of Czar Nicholas. mtDNA can give you your deep ancestral origins of 20,000 to 200,000 years back, but is not generally helpful for genealogy purposes. If you choose this test, go for the full sequence mtDNA.

utosomal DNA, atDNA, is the newest kid on the block. It is the recombined DNA that you get from BOTH parents. Bits of any or all ancestors may be found in this type. You and your sister or brother each get half from mom and half from dad, or 23 chromosomes from each. But you may have bits from different relatives as the recombining is random. You might get more from Aunt Sophie and your sibling might have received more from Uncle Joe. This DNA can give you information to about three to four generations back, and you may find distant cousins. Beyond that time, the percentage of matching DNA dwindles to such a tiny amount that it is difficult to claim any relationship.

By Rosemary McNerney Winkler

Inspired by an article in the June 2015 issue of the Johnson County Kansas Genealogist by Cathy Lawrenz used with permission.